Sound recording apparatus



F. E. RUNGE ET AL 2,015,335

SOUND RECORDING APPARATUS Sept. 24, 1935.

Filed -Aug., 31, 1935 INVENTOR FRANK E. nu THU? a. lMMEPxMAN ORNEY Patented Sept. 24, 1935 UNITED STATES- PATENT orrrcr:

2,015,386 SOUND RECORDING APPARATUS Application August 31, 1933, Serial No. 687,554

4 Claims.

This invention relates .to a photo-optical sound recording apparatus and more particularly to the variety thereof wherein a sound actuated diaphragm vibrates a beam of light by causing the vibration of a mirror and thereby produces a variable impression upon a moving film. The particular structure involved is a unit comprising a diaphragm and optical system adapted for insertion in a sound recording camera of the type wherein the voice of the operator of the camera is recorded upon the film.

One object of the invention is to provide such a unit wherein all the delicate optical and acoustical elements are sealed so as to prevent tampering therewith and to protect them from damage.

Another object of the invention is to provide an extremely compact unit which is capable of functioning as before described.

Another object of the invention is to provide such a unit wherein the optical system isadjustable from the exterior of the device.

Another object of the invention is to provide a two-way adjustment for the mirror of such construction that one adjustment does not appreciably afiect the other.

Referring now to the drawing:

Fig. 1 is a view of the side of the apparatus showing a portion of the lamp house broken away,

Fig. 2 is a transverse section through the diaphragm and optical system unit which appears at the right hand side in Fig. 1,

Fig. 3 is a view of the optical system from the rear, and

Fig. 4 is an enlarged detail showing the mounting of the driving rod of the optical system of the mirror adjustment.

As shown in Fig.1, the entire unit is housed .in a casing I, preferably of cast aluminum or the like, which is divided into several compartments and which carries at its right-hand side the diaphragm unit 2.

One of the compartments in the casting I houses the exciter lamp 3 which is supported in an appropriate socket and has one terminal there- 55 of the housing I which encloses the optical system in contact with the member I 2.

and actuating means therefor, and the light emerges in the form of a beam of minute width through the aperture 29 which is located adjacent to the film upon which sound is to be recorded. This aperture is formed in a plate 1 secured to the 5 casting I by screws and immediately inside of the aperture 29 is located a small cylindrical lens forming one end of the optical system and serving to assist in rendering the beam of light very narrow where it impinges upon the film. 10

The diaphragm unit 2, as shown in greater detail in Fig. 2, includes two casing members, one of them l0 being the front covering of the diaphragm which is made integral with the mouthpiece I I, and the other being the rear member I2 15 which fits against a seat in the right hand end (Fig. 1) of the casting I. The mouthpiece II isprovided with a protective fabric l3 held in place by a ring I l and which serves to prevent dirt and moisture or mechanical interference from reach 20 ing the diaphragm.

The mouthpiece II, is also provided with apertures lfi'which serve to prevent mufiling of the ate the mirror 22 which is mounted, as shown in Fig. 3, upon the diamond-shaped spindle I9 (Fig. 4). The diamond-shaped spindle I9 is provided with bearings, as shown in Fig. 4, in the adjust- 35 able member 20 and the spring 2| which passes around the rod I8 serves to hold the rod I8 snugly against the spindle I9 and to hold the spindle I9 into the said bearings.

It will be apparent that longitudinal oscilla- 0 tion of the rod ill by the diaphragm 15 will cause rotation of the spindle I9 about the said bearings and thereby cause movement of the mirror 22 (Fig. 3).

The adjustable member 20 is provided with a hardened steel ball 23 which fits into a conical recess in its upper surface and upon which presses the spring 24 which holds the member 2|) snugly The member 20 is provided with a hemispherical face on the surface which contacts with, the member l2 so that it can be adjusted in all directions about the center of curvature of the said face.

It will be apparent, from consideration of Fig. 1, that the vibrating mirror 22 of the optical system must be so situated that the beam of light, when no sound is expressed thereon, covers one-half of the aperture 5 and it is, of course, necessary that the beam of light strike centrally upon the said aperture and neither above nor below it, and therefore the adjustments now described are provided.

Seated in the member I2 is a screw 25 carrying, adjustably thereupon, a nut 25 which serves to adjust the arm 21 of the member 20. It will be obvious, of course, that another nut may be used upon the same screw to hold the' arm 21 against the nut 26, but preferably a helical spring is placed around the screw 25 and bearing against the member I2 in the same manner as the hereinafter described in regard to. the other adjustment. It will be apparent that movement of the arm 21 up or down by adjustment of the nut 25 will serve to rotate the hemispherical face of the member 20 against the member l2 and to thereby adjust the mirror spindle IS in its plane of vibration and to thereby adjust the beam of light vertically in position upon the slit 29. This adjustment is usually fairly stable and it is, therefore, not necessary that it be readily accessible from the exterior of the casing of the apparatus.

The rotational adjustment of the mirror, however, is relatively unstable, being afiected by temperature, etc., and it is necessary that this adjustment be readily accomplished in the exterior of the device.

The member 20 is accordingly provided with an arm 28 through which passes the screw 30 which is provided with an appropriate bearing surface to co-operate with the arm 28 which is held firmly thereagainst by the spring 3|. The screw 30 passes freely through the members I and I2 and is fitted with a knurled nut 32 which is held against the outer face of the member ID by the spring, 3|.

It will be apparent that rotation of the nut 32 will move the screw 30 in or out, thereby rotating the member 20 about the axis coinciding in direction with the axis of the mirror spindle l9 and will thereby raise or lower the bearings for the said spindle in the member 20 in relation to the bearing in the rod l8, and will thereby cause rotational adjustment of the mirror spindle about its axis.

A peep-hole 34 is provided in the casing, and

on the back of the member I! is provided a mirror 35in such a position that if an observer looks from the peep-hole 34 he will see the beam of light extend on the near surface of the plate I reflected in the mirror 35 which thereby permits him to make the proper adjustment thereof.

The entire unit is secured to the center plate of the apparatus by means of screws 31 which .retain the optical system in proper co-operative relation with a film drum or the like, supporting the film in front of the aperture 29.

We claim:

1. Photophonographic apparatus including a vibratable mirror spindle, a bearing member provided with a spherical bearing surface and supl5 porting one side of said spindle, a base supporting said member, and means for azfiusting said bearing member about the center of said surface.

2. Photophonographic apparatus including a vibratable mirror spindle, a bearing member provided with a spherical bearing surface and supporting one side of said spindle, a base supporting said member, spring means pressing said support against said bearing, and means for adjusting said bearing member about the center of said surface.

3. Photophonographic apparatus including a vibratable mirror spindle, a bearing member provided with a spherical bearing surface and supporting one side of said spindle, a base supporting i said member, means for adjusting said bearing member about the center of said surface,'a driving rod supporting the other side of said spindle, and resilient means urging said rod against said spindle and thereby retaining said spindle against 351 ARTHUR G. ZIMMERMAN. 

